CVE-2022-31152Network attack vector

Room-state divergence via incomplete event authorization

Published Sep 2, 2022 · Updated Apr 23, 2025

Improper event authorization in Matrix.org Synapse 1.61.0 and earlier allows remote attackers to cause federated room-state divergence. The check_state_independent_auth_rules path accepts m.room.create events with previous events and duplicate or unexpected authorization events instead of rejecting them. Federation must be enabled, and a crafted event from another homeserver can leave participating servers with inconsistent room state and deny consistent room service.

CVSS severity7.5
High
EPSS probability1.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper event authorization in Matrix.org Synapse 1.61.0 and earlier allows remote attackers to cause federated room-state divergence. The check_state_independent_auth_rules path accepts m.room.create events with previous events and duplicate or unexpected authorization events instead of rejecting them. Federation must be enabled, and a crafted event from another homeserver can leave participating servers with inconsistent room state and deny consistent room service.

The record

CVE
CVE-2022-31152
Published
Sep 2, 2022
Updated
Apr 23, 2025
Vendor
Matrix.org
Product
Synapse
Classifications
CWE-703, CWE-755, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 2, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.62.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Matrix.org · Synapseversion=< 1.62.0

Published CVSS scores

7.5NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-703Improper Check or Handling of Exceptional Conditions
CWE-755Improper Handling of Exceptional Conditions
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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